This invention relates to apparatus for twisting a strip of flat material into a helix or other suitable shape.
According to the present invention such apparatus comprises one or more feed rollers adapted to feed the strip into means for guiding and locating the strip in the plane of its longitudinal axis, and from whence the strip passes into twist rolls which are angularly rotatable with respect to the guide means and which are provided with surfaces which grip the strip and when so angularly rotated twist the strip about its longitudinal axis.
The twist rolls are preferably non-driven and the feed rollers feed the strip through the whole of the apparatus.
The means for guiding and locating the strip comprise guide wheels. These are preferably provided by two wheels on parallel spaced apart axes and which have flanged edges the arrangement being such that the strip is rigidly located and guided between the rolls, and their flanged edges.
The twist rolls are preferably in close proximity to the wheels and comprise in turn two wheels on parallel spaced apart axes in each of which has a flange on one side which in combination with a chamfered portion engages the faces of the strip, the flange and chamfered portion on one wheel being opposite to that on the other wheel. Each wheel is also preferably provided with a cylindrical portion which is engaged by or closely abuts the flanges on the other wheel.
The strip may be engaged at its faces or sides by the cylindrical portions.
The guide wheels and twist wheels are preferably located in a housing which is formed in two parts, the guide wheels being located in a part which is fixed while the twist rolls are located in a part which is angularly rotatable with respect to the fixed part. The degree of rotation preferably determines the pitch of the twist.